diff --git a/lisp/Makefile b/lisp/Makefile
index 1b30fb2..6dec1dc 100644
--- a/lisp/Makefile
+++ b/lisp/Makefile
@@ -15,7 +15,7 @@
 #   You should have received a copy of the GNU General Public License
 #   along with CLark. If not, see <http://www.gnu.org/licenses/>.
 DESTDIR ?= /usr/local
-LISP = sbcl --disable-debugger
+LISP ?= sbcl --disable-debugger
 
 binaries = clark
 install-binaries = $(addprefix install-,$(binaries))